As technology advances, various types of computer-operated systems, such as personal computers, hand-held devices, robotic devices, autonomous vehicles, etc., are being employed for performing a variety of functions. As computer-operated systems become increasingly prevalent in numerous aspects of modern life, it is desirable for computer-operated systems to be efficient. Therefore, a demand for efficient computer-based systems has helped open up a field of innovation in sensing techniques, as well as sensor design and assembly.
Sound sensors (e.g., infrasound sensors, microphones, ultrasound sensors, etc.) are sensors used to detect sounds. A sound sensor array is a device that includes multiple sound sensors arranged in predetermined positions relative to one another. A computing device can employ various signal processing techniques to deduce information pertaining to sounds detected by a sound sensor array.
Sound source direction estimation is an example signal processing technique for estimating the direction of a detected sound. In some implementations, this technique may involve using a mixer to sum the signals received from individual sound sensors in the array. Due to offset(s) between positions of the sound sensors in the array, a first sound sensor may detect a sound before a second sound sensor. By accounting for the delay between the two detections, a computing device employing this technique may process the combined signal from the mixer to determine an arrival angle (e.g., direction) of the detected sound.
Sound source localization is an example signal processing technique for estimating the location of a sound source emitting a detected sound. In some implementations, this technique may involve measuring (or estimating) the direction (or angle of arrival) of the detected sound at two (or more) predetermined locations on the array. By accounting for the arrival angles at the two locations, a computing device employing this technique may process outputs from the sound sensor array(s) to estimate (e.g., triangulate) the location of the sound source.
In scenarios where a sound sensor array detects a combination of sounds emitted by multiple sound sources, sound source separation is an example signal processing technique for separating (or recovering) a sound emitted by one of the multiple sound sources. In some implementations, this technique may involve applying one or more statistical algorithms, such as principal components analysis or independent components analysis, to output(s) from the sound sensor array. By applying the one or more statistical algorithms, a computing device employing this technique may identify spectral components of individual sounds in the detected combination of sounds. The computing device may then recover (or estimate) one sound in the detected combination of sounds by removing (e.g., via spectral subtraction, etc.) respective spectral components associated with other sounds in the detected combination of sounds.